Getter device

ABSTRACT

A GETTER ASSEMBLY FOR USE IN A TELEVISION PICTURE TUBE COMPRISING A RECEPTACLE CONTAINING GETTER MATERIAL ARRANGED ON THE INSIDE SURFACE OF THE FUNNEL PORTION OF THE PICTURE TUBE AND HAVING A COVER MEMBER WHICH IS PROVIDED WITH DEFLECTING MEMBERS SO AS TO PREVENT UNDESIRED DEPOSITION OF GETTER MATERIAL WITHIN THE PICTURE TUBE.

United States Patent Reash [45] J GETTER DEVICE Prima Examiner-R0 Lake 75 Inventor: Cl W.R h F P k. U y l 3:; eas alrvlew ar Assistant Examiner-Darwin R. l-lostetter Attorney-Paul A. Rose et al. [73 Assignee: Union Carbide Corporation,

New YOl'k, N.Y. [57] ABSTRACT Filed! 30, 1972 A getter assembly for use in a television picture tube A l N 239 617 comprising a receptacle containing getter material ar- [211 pp 0 ranged on the inside surface of the funnel portion of the picture tube and having a cover member which is U.S. Clp ovided deflecting members so as to prevent uni5 1 Int. Cl. 1101j 19/70 d i d d iti n of getter material within the picture [58] Field of Search 313/174; 417/48 [56] References Cited 3 Claims, 10 Drawing Figures UNITED STATES PATENTS 1/1971 Palsha 313/174 PATENTEUJUM 1 1 m4 amelvae 27 ggF/G: 5 I\ GETTER DEVICE This invention relates to an improved getter assembly for use in television picture tubes. More particularly, the present invention is directed to a getter assembly which minimizes deposition of the getter material at undesirable locations within the picture tube.

In the manufacture of television picture tubes the necessary vacuum is obtained through the use of getters, ordinarily barium getters, whereby barium is flashed or vaporized within the picture tube. The vaporized getter material, e.g., barium, soaks and reacts with the residual gases in the picture tube and removes them as low vapor pressure solid condensates. Also, the barium which is deposited on the interior surfaces of the picture tube continues to sorb gases which may be liberated during use of the picture tube.

In the past, getter devices, commonly in the form of ring shaped containers, were mounted in the neck portion of the picture tube. However, for various practical reasons, it is now the usual practice to position the getter container on the inside surface of the funnel portion of the picture tube. This arrangement has various advantages, however, a significant disadvantage is the deposition of getter material, e.g., barium, on the screen of the picture tube and at other locations where such deposition is disadvantageous. When the barium deposition on the picture screen is excessive, the light out put is reduced with obvious disadvantages. Also, excessive barium deposition on the electron gun, at the junction of the picture tube funnel and screens, and on the tube funnel adjacent the getter are disadvantageous as well known.

It is therefore an object of the present invention to provide a getter assembly whereby the deposition of getter material on the screen of a television picture tube and other sensitive locations is minimized.

Other objects will be apparent from the following description and claims taken in conjunction with the drawing in which FIG. 1 shows somewhat schematically a conventional picture tube and electron gun arrangement together with a known getter support which incorporates the novel shielded getter arrangement of the present invention FIG. 1A is a cross-sectional view of the device of FIG. 1

FIG. 2 shows a plan view of the bottom portion of a solid center getter container FIG. 3 shows and elevation view of the device of FIG.

FIG. 4- shows a plan view of a getter cover for use in conjunction with the device of FIG. 2

FIG. 5 is an elevation view of the getter cover of FIG. 4

FIG. 6 is a plan view of the assembled device of FIG. 7

FIG. 7 and 7A show an assembly of the devices of FIGS. 2 and 3 FIG. 8 is an enlarged fragmented sectional view of the device of the present invention.

A getter arrangement in accordance with the present invention comprises, in combination, a picture tube havinga conical funnel portion and a screen surface, a getter device having an annular channel containing getter material arranged adjacent to the funnel portion of the picture tube, the annular channel being sealed at its bottom adjacent the funnel portion of the picture tube, the upper portion of the annular channel being directed toward the interior of the picture tube a covering member attached to the getter device providing essentially total closure of central segments of the upper portion of the annular channel, with openings to the annular channel being provided only at opposed locations oriented away from the screen surface of the picture tube and upwardly slanting deflecting members attached to the getter device and arranged above said openings whereby getter material expelled from the annular channel is directed away from the getter device.

With reference to the drawing, FIG. 1 shows a conventional television picture tube 1 having a funnel portion 3', a neck portion 5, and a screen 7, e.g., a tri-color screen formed by techniques well known in the art.

An electron gun, shown schematically at 9, is located within the tube neck 5. An elongated spring member 11, attached to electron gun 9 and getter assembly 13, together with attached wire support members 14, maintains getter assembly 13 in a position adjacent to the funnel portion 3 in a well known manner. Getter assembly 13 includes a cover member 15, in accordance with the present invention, which is hereinafter more fully described.

In operation, conventional R-F heating coil l7 flashes the getter material in getter assembly 13 in a known manner whereby the vaporized getter, e.g., barium is expelled into the picture tube I as hereinafter described.

With reference to FIGS. 2 and 3, a cylindrical getter container suitably formed of stainless steel, is shown at 19 having an up-raised bottom portion 21 which forms an annular channel 23 in which is pressed a getter material 24 in the usual manner. For television picture tubes the getter material may be, for example, 1,000 mg of a 25 per cent barium 25 per cent aluminum, 50 puent nickel exothermic alloy yielding about 225 mg of barium upon flashing. As is well known, the flashing of the getter requires heating to a high temperature, about l,300 C, to vaporize the barium or whatever getter material is used. In the present invention, the vaporized getter material is directed into the picture tube in a particular manner utilizing the cover member illustrated in FIGS. 4 and 5. The cover member 15, suitably of stainless steel, is shown to be circular in shape having flat portions 25, a depressed center portion 27 and upturned, opposed segments 29. In the assembly of the present invention as illustrated in FIGS. 7 and 7A, cover member 15 is placed over getter container 19 and is affixed thereto, e.g., by a spot weld indicated at 31 in FIGS. 7 and 7A. Cover member 15 fits closely within container 19 and is configured such that the flat portions 25 cover and effectively seal the central segments of the upper surface of the channel 23 which otherwise would have line of sight access to the parts of the tube envelope where a minimization of the barium deposit is desired, preferably a major portion. The upturned segments 29 establish openings 32 to the channel 23 whereby vaporized getter material expelled from the channel 23 is permitted to enter the picture tube 1.

As can be seen with reference to FIGS. 1 and 1A getter assembly 13 is arranged in the picture tube 1 so that the chordal upturned segments 29 are at locations 33 which are oriented away from the picture tube screen 7, i.e., the openings 32 are in line with the circumference of the conical funnel portion as indicated at 35. Another way of describing the position of openings 31 is that they are arranged in line transverse to the slope 37 of the funnel portion which passes through the getter device.

With the getter assembly 13 arranged as indicated, upon flashing, vaporized getter material is expelled from annular channel 23 through predetermined openings 31 and the vaporized getter exiting container 19 is deflected by segments 29 in a direction away from the picture screen 7 and also away from electron gun 9 as can be seen in FIG. 1A.

The arrangement of segments 29, and the shielding provided by flat portions 25, directs the deposit of getter material away from the tube screen 7 and electron gun 9. Also, as can be readily seen from FIG. 8, with cover member recessed in getter container 19 as shown, the vertical extended portion 40 of getter container 19 prevents the formation of a heavy deposit of getter material on the funnel next to the getter assembly 13, which could lead to ionization or cracking of the glass.

In the present invention, the slant angle of segments 29 can suitably range from about 15" to 30 and by variation of this angle, and with adjustment of the height of the extended portion 40 of getter container 19, getter deposition on screen 7 can be readily controlled and thereby minimized.

In some instances, to avoid over-heating by RF dur-.

ing flashing, verysmall slots or holes, 0.020 inch thick and less, may be provided in the getter cover as indicated at 40 and 42 in FIG. 4.

By way of specific example, a getter assembly was made with a container of 305 stainless steel having an outer diameter of 0.765 inch. The height of the con tainer sides was 0.165 inch, the width of the getter channel was 0.222 inch and the height of the up raised center portion was 0.085 inch. The cover for the getter container was formed from 305 stainless steel and had a diameter of 0.745 inch. The flat portion of the cover was recessed 0.029 inch below the top of the container side and the deflecting members were slanted upward at an angle of about 20 at a distance of 0.145 inch from the center and the tips were 0.035 inch above the top of the getter container.

The getter material contained 250 milligrams of barium and the getter was arranged and flashed in a 19 inch, deflection picture tube as shown in FIG. 1. While the amount of barium vaporized into the tube was the same as when no cover member was used, the

barium deposition on'the screen of the tube was sub-- other metals and alloys used in conventional getter devices.

What is claimed is:

1. In combination, a picture tube having a conical funnel portion and a screen surface, a getter device having an annular channel containing getter material arranged adjacent to the funnel portion of the picture tube, the annular channel being sealed at its bottom adjacent the funnel portion of the picture tube, the upper portion of the annular channel being directed toward the interior of the picture tube, a covering member attached to the getter device providing essentially total closure of central segments of the upper portion of the annular channel, with openings to the annular channel being provided only at opposed locations oriented away from the screen surface of the picture tube and upwardly slanting deflecting members attached to the getter device and arranged above said openings whereby getter material is expelled from the annular channel is directed away from the getter device.

2. A combination in accordance with claim 1 wherein the covering member comprises an annular portion of substantially the same diameter as the annular channel having upturned outer edges which form the deflecting members and provide the openings to the annular channel.

3. In combination, a picture tube having a conical funnel portion and a screen surface, a getter device arranged adjacent to the funnel portion of the picture tube comprising a cylindrically shaped metal receptacle having an open top and having an up-raised bottom portion which defines an annular channel in said receptacle, getter material within said annular channel and a recessed circular metal cover member overlying the channel of said receptacle and attached thereto at its up-raised bottom portion, opposed segments of the cover member at locations oriented away from the screen surface being turned upward to permit exit of getter material from the receptacle. 

